What's eating my 'romanesco' broccoli?

Romanesco broccoli faces the same brassica pest gauntlet as other heading brassicas. Cabbage white caterpillars tunnel into the tight spirals and are almost invisible until damage is done. Cabbage aphids form dense waxy colonies on leaves, and imported cabbageworm is a constant pressure. Pigeons and wood pigeons strip young plants in the UK.

Green caterpillars blend into foliage and bore into developing heads, leaving frass inside the spiral curd where it is hard to wash out. Fine insect-proof netting (mesh <0.8 mm) from transplant stage is the gold standard. Apply Bt (Bacillus thuringiensis var. kurstaki) to foliage weekly. Hand-pick eggs and caterpillars.

Dense, mealy grey-blue colonies on leaf undersides and within the curd; honeydew leads to sooty mold; heavily colonised heads are unmarketable. Blast off early colonies with water. Neem oil or insecticidal soap sprays. Avoid excess nitrogen. Encourage parasitic wasps (Diaeretiella rapae) — leave some flowering weeds nearby.

Maggots tunnel into roots, causing sudden wilting and blue-tinged leaves; young transplants collapse; adult flies lay eggs at base of stem. Place brassica collars (10 cm discs of carpet underlay or cardboard) flat around each stem at transplanting to prevent egg-laying at the soil surface.

Pigeons strip leaves down to bare stalks, particularly over winter when Romanesco is maturing. Damage can be total on unprotected plants. Fine mesh or dedicated bird netting over hoops is the only reliable defence. Scarecrows and CDs provide short-term deterrence only.